T. Salehi; D. Yousefi Kebria
Abstract
The present study focused on the synergistic effects bioremediation of phenol in aqueous solution using combination of anaerobic mixed culture and Granular Activated Carbon (GAC) as a biological GAC (BGAC). Meanwhile, the effect of contact time and various phenol concentrations on adsorption and ...
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The present study focused on the synergistic effects bioremediation of phenol in aqueous solution using combination of anaerobic mixed culture and Granular Activated Carbon (GAC) as a biological GAC (BGAC). Meanwhile, the effect of contact time and various phenol concentrations on adsorption and biosorption process investigated. The phenol concentration was analyzed using UV/Vis spectrophotometer. The morphology and structure of two adsorbents (GAC and BGAC) were characterized by FESEM and BET specific surface area analysis. The batch experiments using mixed bacterial culture, isolated from wood and paper factory wastewater, were adapted to high concentrations of phenol and employed in order to evaluate the tolerance and biosorption capability of microorganisms for phenol biodegradation. The synergetic effect of phenol removal using combination of GAC with an anaerobic biofilm indicated that the removal efficiency for concentration of 700, 800, and 1000 mg/l at initial stages increased to 4, 10, and 12%, respectively and while by increment of the retention time did not shown significant impact on the removal efficiency. These results conducted both desorption of adsorbates due to biotransformation in the aqueous solution and direct assimilation of adsorbates on GAC by the microorganism’s biofilm. The adsorption data were fitted with pseudo-first-order and pseudo-second-order models and it was found that the pseudo-second-order model explains the adsorption kinetics more efficiently. The compatibility of the Freundlich and Langmuir adsorption models to equilibrium data were investigated. In fact, the Langmuir isotherm was found to be the best fitting isotherm.
O. O. Obiukwu; M. N. Uchechukwu; T. Uchechukwu
Abstract
Biodegradable composites (SCB-PES) and a control sample were developed from polyester resin (PES) matrix and sugar cane bagasse (SCB) fibre at different matrix- fibre compositions using the compression technique. The effects of fibre content (9–54 wt%) and fibre treatment on thermal and dynamic ...
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Biodegradable composites (SCB-PES) and a control sample were developed from polyester resin (PES) matrix and sugar cane bagasse (SCB) fibre at different matrix- fibre compositions using the compression technique. The effects of fibre content (9–54 wt%) and fibre treatment on thermal and dynamic mechanical properties of polyester / sugar cane bagasse fibre biocomposites were evaluated via thermogravimetric analysis (TGA) and DMA (Model: DMA 242 E Artemis) storage modulus (E1), loss modulus (E11), change in length of modulus (∆l), tan delta (E11/ E1) and glass transition temperature (Tg). The results showed that while the weight of the pure PES matrix showed a near complete disappearance between 400 –500 0C, the 9 % FW SCB-PES composite lost nearly 50% of its weight, in the same temperature region. The results which show that SCB-PES composites demonstrated acceptable thermal and abrasion properties portrays the effectiveness of SCB as reinforcement for PES matrix and the potential of the eco-friendly composites in the fabrication of utility materials for sustainable development. The weight loss (wt%) by the composites after 6 months soil burying test ranged from 22.24 -85.34 %.
A. Abderrahim; M. M. Boudia; N. Ghellai; Y. Menni; H. Ameur
Abstract
This paper aims to determine the wind potential in two regions of Algeria according to months, seasons, and entire years. An attempt is made to participate to the update of the wind map in this country, by using the collected hourly data during a period of more than thirty years. The Weibull function ...
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This paper aims to determine the wind potential in two regions of Algeria according to months, seasons, and entire years. An attempt is made to participate to the update of the wind map in this country, by using the collected hourly data during a period of more than thirty years. The Weibull function is employed to perform the wind data analysis. Two regions are considered: Ilizi and Oran, which are located in the southeast and northwest of Algeria, respectively. The values of the Weibull parameters, average power density, and mean velocity are employed to achieve the statistical analysis. At the height of 10 m from the ground, the obtained results revealed that the highest annual average rate of 6.5 m/s occurred at the city of 'Illizi'. It was also found that the city of 'Es-senia' has a middle potential of wind with an annual mean velocity of 3.5m/s. Furthermore, it was observed that the spring season is the most windy season for both regions.
K. M. Akkoli; S. A. Goudadi; M. M. Shivashimpi; S. N. Topannavar
Abstract
An analysis of the experimental characterization of the three agricultural residues redgram stalk, soyabean stalk, and chilli stalk (biomass) was carried out and the higher heating values (HHV) were determined using the available correlations from the literature. The selected agricultural residues proximate ...
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An analysis of the experimental characterization of the three agricultural residues redgram stalk, soyabean stalk, and chilli stalk (biomass) was carried out and the higher heating values (HHV) were determined using the available correlations from the literature. The selected agricultural residues proximate analysis results show moisture about 4.2 to 7.4%, the volatile matter about 79.3 to 85.8%, fixed carbon about 4 to 8.94%, and ash about 2.5 to 5.5%. The ultimate analysis results present elemental compositions such as carbon about 46 to 49%, hydrogen about 5%, oxygen about 30%, and the nitrogen about 3.1 to 3.7% with very low sulfur content. The HHV of agricultural residues varies from 14MJ kg-1 to 19MJ kg-1. The design of the downdraft gasifier to accommodate agricultural residues was carried out taking into account the characteristics of the agricultural residues and the specifications of the internal combustion (IC) engine. The characteristics of the agricultural residues depict that the three agricultural residues are suitable for gasification and can be used in a single gasifier.
F. O. Aweda; T. K. Samson
Abstract
Solar radiation is an important parameter in the study of electricity and/or thermal system installation. Direct monthly irradiance data measurements of the earth’s horizontal surface irradiance for the year 1985 to 2019 for nine stations (Sokoto, Birnin Kebbi, Maiduguri, Ilorin, Calabar, Port-Harcourt, ...
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Solar radiation is an important parameter in the study of electricity and/or thermal system installation. Direct monthly irradiance data measurements of the earth’s horizontal surface irradiance for the year 1985 to 2019 for nine stations (Sokoto, Birnin Kebbi, Maiduguri, Ilorin, Calabar, Port-Harcourt, Enugu, Iwo, and Ikeja) were collected from the achieve of HelioClim satellite website. The stationarity of the series was determined using the time plot of the irradiance data between the periods under study but the formal test of stationarity was carried out using the Augmented Dickey-Fuller (ADF) test with a p-value less than 0.05 signifying stationarity. Different autoregressive integrated moving average (ARIMA) models were fitted to the irradiance data for each of the selected stations. The results revealed that Sokoto, Maiduguri, and Kebbi have their maximum solar irradiance at about and their minimum at about , while Ilorin has its maximum solar irradiance at about and its minimum solar irradiance at about . Ikeja, Iwo and Port-Harcourt, Calabar and Enugu have their maximum solar irradiance and their minimum solar irradiance at about . It is therefore concluded that for Kebbi, Iwo and Maiduguri, the best model was ARIMA (3,0,3), for Calabar and Sokoto, it was ARIMA (2,0,2) while for other locations like Enugu, Ikeja, Ilorin and Port Harcourt, ARIMA (2,0,3) was the best model for forecasting irradiance in these study areas. The forecasted values of irradiance between January till December 2020 with its corresponding 95% confidence levels indicate good prediction of solar irradiance for future occurrence.
R. Farzandi; H. Nayebzadeh; M. Hokmabadi; N. Saghatoleslami
Abstract
The effect of cultivation culture on the biodiesel yield produced from in-situ transesterification of Chlorella vulgaris microalgae was assessed. Firstly, the algae were cultivated in Moh202, sterilized wastewater (SW), unsterilized wastewater (USW) mediums. It was found that around ten days were suitable ...
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The effect of cultivation culture on the biodiesel yield produced from in-situ transesterification of Chlorella vulgaris microalgae was assessed. Firstly, the algae were cultivated in Moh202, sterilized wastewater (SW), unsterilized wastewater (USW) mediums. It was found that around ten days were suitable to receive maximized growth of microalgae; while, maximum and minimum growth was detected in Moh202 and SW media. Before assessment, the effect of cultivation medium on the biodiesel content, the transesterification reaction conditions such as catalyst (NaOH) concentration, reaction time and amount of methanol were investigated by algae cultivated in Moh202 medium via fractional factorial design as statistical methodology. In the range of the study, catalyst concentration and reaction time were the most important effective parameters on the biodiesel yield. Moreover, the interaction between reaction time with catalyst concentration and amount of methanol was also important. In short reaction time and its interaction with catalyst concentration had positive effect, while catalyst concentration, amount of methanol and interaction of reaction time and amount of methanol had negative impact on the biodiesel yield. The yields of the algae cultivated in Moh202, sterilized and unsterilized wastewater media at the optimum conditions of 1 wt.% of catalyst, 9 mL methanol/g biomass and reaction time of 4 hours were 95.5%, 83.9% and 75.5%, respectively. Although the difference between biodiesel yields of Chlorella vulgaris Microalgae cultivated in the wastewater medium compared to sterilized wastewater medium was observed, wastewater can be used as a medium for cultivation of algae for biodiesel production to reduce the biodiesel production costs.
A. G. Adeniyi; J. O. Ighalo
Abstract
In this preliminary investigation, the production of liquid fertilizer from rock phosphate and dolomite in Nigeria using the nitrophosphate is evaluated. Rock phosphate was obtained from Sokoto state, Nigeria. Dolomite was obtained from Edo state, Nigeria. This work contains a detailed description of ...
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In this preliminary investigation, the production of liquid fertilizer from rock phosphate and dolomite in Nigeria using the nitrophosphate is evaluated. Rock phosphate was obtained from Sokoto state, Nigeria. Dolomite was obtained from Edo state, Nigeria. This work contains a detailed description of the procedure and the associated chemical reactions. There are also important explanations of some physical observations and their possible implications in a large scale process. The time frame for each batch should not exceed 1 h considering the reaction rates and the temperatures are likely not to exceed 80oC at any point in the process. It was observed that the potassium, phosphorus and nitrogen content of both fertilizers are similar but the calcium content of the product from dolomite was higher than the other products. Furthermore, possible process design modifications based on these physical observations are proposed in line with product quality, safety, cost and other considerations. The process was ultimately successful and recommendations were made based on several aspects of the process.
S. W. Igo; N. Kokou; A. Compaoré; P. Kalifa; G. L. Sawadogo; D. Namoano
Abstract
This work is devoted to the evaluation of the performance of a typical fired-wood oven commonly used in the rotisserie sector in Burkina Faso. The methodology used is based on the energy balance of the oven. For this purpose, 20 liters of water were heated up to 90 °C. The difference in water temperature ...
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This work is devoted to the evaluation of the performance of a typical fired-wood oven commonly used in the rotisserie sector in Burkina Faso. The methodology used is based on the energy balance of the oven. For this purpose, 20 liters of water were heated up to 90 °C. The difference in water temperature at the start and at the end of the experiment makes it possible to calculate the amount of energy consumed by the load. The temperatures of the walls as well as that of the ambient were recorded to evaluate the losses by convection towards the environment. The losses through the fumes have been estimated from the energy balance. The results show that the dominant losses are those of fumes (about 55 % of the energy consumed). The losses through the walls are relatively large (26 %). The efficiency of the oven is around 19 %, which is very low. These results show that these equipment are inefficient and contribute significantly to the waste of wood at the national level.
S. O. Ayoola; C. E. Ejikeme; O. Folami
Abstract
The toxicity effects of crude oil were investigated in the laboratory. Triplicates of (T1) 0.25mg/l, (T2) 1.0mg/l, (T3) 2.25mg/l, (T4) 5.0mg/l and (T5) 7.5mg/l concentration of crude oil exposed to Sarotherodon melanotheron species. The acute toxicity test of crude oil when tested against Sarotherodon ...
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The toxicity effects of crude oil were investigated in the laboratory. Triplicates of (T1) 0.25mg/l, (T2) 1.0mg/l, (T3) 2.25mg/l, (T4) 5.0mg/l and (T5) 7.5mg/l concentration of crude oil exposed to Sarotherodon melanotheron species. The acute toxicity test of crude oil when tested against Sarotherodon melanotheron revealed that the derived toxicity index LC50 was 0.925mg/l. On computing Toxicity Factor (TF), using 96 hours. LC50, crude oil was found to be very toxic to the Sarotherodon melanotheron juvenile. The mean frequencies of micronucleus in S. melanotheron exposed to different concentration of crude oil ranged from 3.01±0.50 – 27.48±2.71. The lowest value was 3.01±0.50 in T0 (control) while the highest value of 27.48 ± 2.71 wasrecorded in fishes exposed to (T5) 7.5mg/l test solutions. The results obtained from micronucleus test showed that T5 had the highest number of micro-nucleated cells followed by T4 while T1, T2, T3, and T0 significantly increased with the concentration across the test chemical. Sarotherodon melanotheron showed various degrees of sensitivity in monitoring genetic damage especially in the normal nucleus (NN). The chromosomal aberrations indicate formation of vacuolated nucleus (VC), micronucleus (MN) and bi-nucleated cells (BN) showed marked increase in occurrence in the following concentrations of occurrences; T1, T2, T3, T4 and T5, respectively. Test solution of concentration T5 (7.5mg/l) was observed to possess fish with highest level of micronucleus frequencies followed by T4 (5.0mg/L). There were significant differences in increasing T5 having the highest number of micro-nucleated cells (MN) with a trend in increasing bi-nucleus cells (BN), polymorphic nucleus (PM), kidney shape nucleus (KN) and bleb nucleus (BLN) cells, respectively, as the concentration of the test chemical increased. The results also showed that there was a significant difference in the effects of the T5 and other test concentrations (T1, T2, T3, T4 and T0). The response of Sarotherodon melanotheron established that is a better model for bioassay test used as a pollution bio indicator. Pollutants even in a very low concentration if present for a long duration may affect the nucleus. Hence, the use of any kind of substances such as crude oil products and synthetic chemicals in aquaculture field should be carefully monitored and used under proper guidance.
S. N. Ashrafizadeh; Z. Seifollahi
Abstract
This article was written at the same time as the corona virus peaked in the country and during home quarantine, coinciding with the 40th day of the corona virus entering the country in April 2020, coincided with the Iranian new-year holidays. The purpose of writing this brief is to express sympathy with ...
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This article was written at the same time as the corona virus peaked in the country and during home quarantine, coinciding with the 40th day of the corona virus entering the country in April 2020, coincided with the Iranian new-year holidays. The purpose of writing this brief is to express sympathy with the earth and respond to her forgotten groans. A late but at the same time insignificant activity in the hope of healing the wounded conscience of inactive scholars such as current writers who hope to take positive action to preserve and protect the earth, the human ecosystem. The emphasis and purpose of this article is to exemplify national determination and mobilization in the fight against Corona for a higher purpose such as saving the earth and human life from catastrophe. In this regard, the teaching of environmental requirements in educational levels, the development of elite discourse in the framework of the formation of non-governmental organizations, and the use of scientific, cultural, and indigenous capacities as viable solutions have been proposed.
